Sudden cardiac arrest remains a serious public health issue. Approximately 350,000 individuals are stricken in the U.S. annually, with overall survival rates on the order of only 5%. Even with the immediate availability of the most advanced care currently available, a survival rate of 25% appears to be the probable best case scenario. Improved therapies to deal with this situation are clearly needed. Prior studies have shown that moderate hypothermia (approximately 3-5 degrees C) provided during and after cardiac arrest can reduce the level of damage to vital organs, including the brain. However, conventional noninvasive means which are available for cooling (such as water-filled cooling blankets and cool air-emitting coverings) are too slow for optimal treatment. Furthermore, they are not well-suited to being used during administration of cardiopulmonary resuscitation (CPR). In a series of recent experiments we have demonstrated that whole body cooling can be achieved using a system (the ThermoSuit System, or TSS) which circulates a thin layer of cold water over the skin surface of an experimental animal. The results indicate that the technique is extremely effective in reducing core temperature. For example we can cause an average 8 degree drop in the core temperature of sedated animals (n=6, mean mass = 37Kg) in 30 minutes Thus in the work proposed here, we seek to extend the results completed in Phase I so that a prototype clinical device can be developed using this technology. This suit can also be used during CPR. The proposal will [1] Develop a combined suit design and temperature control system to rapidly alter body temperature in animals with normal and compromised circulatory systems. [2] Develop a self contained energy storage system based on ice.[3] Develop an operator interface and suit system to be used clinically in the emergency room. [4] Submit documentation to the FDA to receive an IDE for clinical testing.